rol

Rotate left (Register)

Performs a rotate left of xs1 by the amount in least-significant log2(XLEN) bits of xs2.

This instruction must have data-independent timing when extension Zkt is enabled.

Assembly format

rol xd, xs1, xs2

Decode Variables

Bits<5> xs2 = $encoding[24:20];
Bits<5> xs1 = $encoding[19:15];
Bits<5> xd = $encoding[11:7];

Execution

if (implemented?(ExtensionName::B) && (CSR[misa].B == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg shamt = (xlen() == 32) ? X[xs2][4:0] : X[xs2][5:0];
X[xd] = (X[xs1] << shamt) | (X[xs1] >> (xlen() - shamt));

Exceptions

This instruction may result in the following synchronous exceptions:

  • IllegalInstruction

Encoding

svg

Defining extension

(Zbb || Zbkb)

Access

M

Always

Containing profiles

  • Mandatory: None

  • Optional: None